Autosomal Recessive Robinow Syndrome is a rare genetic disorder characterised by abnormalities of the skeletal system, head, face and external genitalia. Affected individuals have shortened bones in the arms and legs, wedge shaped vertebrae, curved spine and short stature. Dysmorphic facial features, underdeveloped genitalia and oral anomalies are also observed in patients. Phenotypic presentation in patients with Robinow Syndrome is related to the inheritance pattern and those with the recessive form have more severe symptoms; the main discriminating feature being the occurrence of multiple rib and vertebral anomalies. Pulmonary or cardiac complications are also common in affected individuals. Intelligence is normal in most cases although some degree of mental retardation occurs in few (20%). While the incidence of Robinow syndrome is about 1:500,000, the prevalence is slightly lower since 5-10% of patients die in infancy or early childhood.
Homozygous loss-of-function mutations in the gene encoding receptor orphan receptor tyrosine kinase 2 (ROR2), located on chromosome 9q22.31, are responsible for autosomal recessive Robinow syndrome. ROR2 gene encodes a homodimer protein that is expressed at high levels during early embryonic development, which promotes osteogenesis and is considered to be essential for cartilage and growth plate development.